As we joined the big crowd I got _____ from my friends.

A．separated

B．spared

C．lost

D．missed

11．下列说法正确的是    

A．激光可用于测距

B．激光能量十分集中，可用于加工金属或非金属材料

C．外科研制一种新型“激光刀”有效减少细菌的感染.

D．激光用于全息照相.有独特优点.